Along with technology development, portable terminals, such as a mobile phone, a PDA, a PMP, a navigation, and a laptop, additionally provide the functions, such as a DMB, a wireless internet, a near field communication between the devices, in addition to fundamental functions, such as call, video/music playbacks, and navigation. Accordingly, the portable terminal includes a plurality of antennas for a wireless communication, such as a wireless internet and a Bluetooth.
In addition, there is a recent trend that the functions, such as information exchange between the terminals, payment, ticket reservation, and search, using a near field communication (i.e., NFC, Magnetic Secure Transmission (MST)) are applied to the portable terminal. For this purpose, the portable terminal is mounted with an antenna module for the mobile terminal (i.e., an NFC antenna module) used in a near field communication method. In this time, the NFC antenna module used is one of electronic tags (RFID), and as a non-contact type near filed communication module using a frequency band of about 13.56 MHz, sends data between the terminals at a short distance of about 10 cm. In addition to payment, the NFC is widely used for transmission of product information at a supermarket or a store and travel information for a visitor, transportation, a lock device for access control, etc.
Recently, there is a trend that a cover of a metal material (hereinafter, a metal cover) is increasingly applied to a portable terminal such as a tablet and a mobile phone. In this time, as illustrated in FIG. 1, when the whole rear cover 11 of the portable terminal is formed with a metal material, there is a problem that it is difficult to implement performance of an NFC antenna 13 mounted on a main body 12 of the portable terminal. Accordingly, the research for implementing performance of the NFC antenna continues to proceed.
As an example, as illustrated in FIG. 2, a conventional portable terminal 20 to which a metal cover 21 is applied forms a slit 22 (or an opening portion) on the metal cover for implementing performance of the NFC antenna, and mounts the NFC antenna to partially overlap with the slit 22. Accordingly, it is possible to implement performance of the NFC antenna through a coupling effect between the NFC antenna and the metal cover through the slit 22.
However, when forming a slit or an opening portion in order to implement performance of the NFC antenna, there are the problems in that a manufacturing process of the portable terminal becomes complicated to thus increase manufacturing costs, and the limitation that should reflect a slit or an opening portion in an exterior design occurs.
Meanwhile, as illustrated in FIGS. 3 and 4, as the user circumstance of the portable terminal recently becomes various, a user demand for a structure that can perform a near field communication in the vertical direction (i.e., a side surface of the portable terminal) as well as in the horizontal direction (i.e., a rear surface of the portable terminal) is increasing.
However, as illustrated in FIG. 5, since a conventional NFC antenna 30 is formed in the shape winding a coil pattern 32 on an upper surface of a ferrite sheet 31, there is a problem in that it is difficult to implement antenna performance in the vertical direction thereof.